A teacher shouting at the top of his lungs emits about 1.0 W of energy as sound waves. Student A is standing 2.0 m away. Student B is standing 20 m away. Compare the sound intensity level at these two locations. OB1 =B₂ B₁ = 10B2 none of the given 10ß1 = ³2 100ß1 = ³2 B1 = 10032

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Chapter16: Wave Motion
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**Sound Intensity Level Comparison**

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**Question:**
A teacher shouting at the top of his lungs emits about 1.0 W of energy as sound waves. Student A is standing 2.0 m away. Student B is standing 20 m away. Compare the sound intensity level at these two locations.

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**Answer Choices:**

- ○ β₁ = β₂
- ○ β₁ = 10β₂
- ○ none of the given
- ○ 10β₁ = β₂
- ○ 100β₁ = β₂
- ○ β₁ = 100β₂

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**Explanation:**
To solve this question, we need to understand that the intensity of sound decreases with distance. The intensity (I) of a sound is inversely proportional to the square of the distance (r) from the source. This relationship can be given by the formula:

\[ I \propto \frac{1}{r^2} \]

In this context, β₁ represents the sound intensity level at Student A's location (2.0 m away), and β₂ represents the sound intensity level at Student B's location (20 m away). Because the energy of sound dissipates as it moves further away from the source, the sound intensity levels at these two points are related as follows:

- For Student A (r₁ = 2.0 m), the intensity I₁ is proportional to \(\frac{1}{2^2} = \frac{1}{4}\)
- For Student B (r₂ = 20 m), the intensity I₂ is proportional to \(\frac{1}{20^2} = \frac{1}{400}\)

Thus, you can see the ratio of the intensities can be calculated:

\[ \frac{I₁}{I₂} = \frac{\frac{1}{4}}{\frac{1}{400}} = 100 \]

This means that the sound intensity level at Student A's location (2.0 m away) is 100 times that at Student B's location (20 m away).

Thus, the correct answer according to our options is:

- ○ β₁ = 100β₂
Transcribed Image Text:**Sound Intensity Level Comparison** --- **Question:** A teacher shouting at the top of his lungs emits about 1.0 W of energy as sound waves. Student A is standing 2.0 m away. Student B is standing 20 m away. Compare the sound intensity level at these two locations. --- **Answer Choices:** - ○ β₁ = β₂ - ○ β₁ = 10β₂ - ○ none of the given - ○ 10β₁ = β₂ - ○ 100β₁ = β₂ - ○ β₁ = 100β₂ --- **Explanation:** To solve this question, we need to understand that the intensity of sound decreases with distance. The intensity (I) of a sound is inversely proportional to the square of the distance (r) from the source. This relationship can be given by the formula: \[ I \propto \frac{1}{r^2} \] In this context, β₁ represents the sound intensity level at Student A's location (2.0 m away), and β₂ represents the sound intensity level at Student B's location (20 m away). Because the energy of sound dissipates as it moves further away from the source, the sound intensity levels at these two points are related as follows: - For Student A (r₁ = 2.0 m), the intensity I₁ is proportional to \(\frac{1}{2^2} = \frac{1}{4}\) - For Student B (r₂ = 20 m), the intensity I₂ is proportional to \(\frac{1}{20^2} = \frac{1}{400}\) Thus, you can see the ratio of the intensities can be calculated: \[ \frac{I₁}{I₂} = \frac{\frac{1}{4}}{\frac{1}{400}} = 100 \] This means that the sound intensity level at Student A's location (2.0 m away) is 100 times that at Student B's location (20 m away). Thus, the correct answer according to our options is: - ○ β₁ = 100β₂
### Sound Intensity Level Conversion Problem

You are overhearing a very heated conversation that registers 80 dB. You walk some distance away so that the intensity decreases by a factor of 100. What is the sound intensity level now?

- [ ] 20 dB
- [ ] 100 dB
- [ ] 90 dB
- [ ] 70 dB
- [ ] 60 dB
- [ ] 0 dB
- [ ] 50 dB
- [ ] 30 dB
- [ ] 80 dB

#### Explanation:
The sound intensity level, measured in decibels (dB), is a logarithmic measure of the intensity of a sound. The formula for sound intensity level is given by:

\[ L = 10 \log \left( \frac{I}{I_0} \right) \]

where:
- \( L \) is the sound intensity level in decibels (dB),
- \( I \) is the sound intensity,
- \( I_0 \) is the reference sound intensity, usually the threshold of hearing.

Given:
- Initial sound intensity level \( L_i = 80 \text{ dB} \)
- Intensity decreases by a factor of 100.

To find the new sound intensity level \( L_f \), we use the relationship of the logarithmic scale:
\[ L_f = L_i - 10 \log(100) \]
\[ L_f = 80 - 10 \cdot 2 \]
\[ L_f = 80 - 20 \]
\[ L_f = 60 \text{ dB} \]

So, the new sound intensity level is:
- [x] 60 dB
Transcribed Image Text:### Sound Intensity Level Conversion Problem You are overhearing a very heated conversation that registers 80 dB. You walk some distance away so that the intensity decreases by a factor of 100. What is the sound intensity level now? - [ ] 20 dB - [ ] 100 dB - [ ] 90 dB - [ ] 70 dB - [ ] 60 dB - [ ] 0 dB - [ ] 50 dB - [ ] 30 dB - [ ] 80 dB #### Explanation: The sound intensity level, measured in decibels (dB), is a logarithmic measure of the intensity of a sound. The formula for sound intensity level is given by: \[ L = 10 \log \left( \frac{I}{I_0} \right) \] where: - \( L \) is the sound intensity level in decibels (dB), - \( I \) is the sound intensity, - \( I_0 \) is the reference sound intensity, usually the threshold of hearing. Given: - Initial sound intensity level \( L_i = 80 \text{ dB} \) - Intensity decreases by a factor of 100. To find the new sound intensity level \( L_f \), we use the relationship of the logarithmic scale: \[ L_f = L_i - 10 \log(100) \] \[ L_f = 80 - 10 \cdot 2 \] \[ L_f = 80 - 20 \] \[ L_f = 60 \text{ dB} \] So, the new sound intensity level is: - [x] 60 dB
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